Rose of Sharon, Hibiscus syriacus.

I agree with gg48 that it looks like Rose of Sharon. I prefer the perennial hardy hibiscus because they are easier to control - but you do have to be diligent about removing seed capsules or cutting the stems down early to keep them from seeding around. I removed the shrubby Rose of Sharon in favor of the herbaceous hardy hibiscuses.

Where do you live/what zone are you in?

I'm in zone 7b.

can be invasive in some areas.. i dont recommend intentionally propagating it around your yard ...

zone means minimum winter temp.. rather useless info.. give us a big city name ... and state if not obvious...

once established.. these are run it over with the car plants.. no care needed ... and can be pruned back rather heavily.. if size matters ... somewhat obvious.. since that is what it did to itself last year ...

i suspect some issue with transplanting lead to its decline.. yet it survived.. with nothing from you.. so dont go loving it to death ....

ken

Yep, Rose of Sharon -- a shrub or pruned as a small tree.